The present invention relates to composite decking, and more particularly to composite decking coextruded with continuous reinforcing strands that improve the structural characteristics of the decking.
Decks, docks, and other platform-like structures typically are constructed from wood, particularly in North America. Generally, both the decking surface and underlying joists or other support structures are constructed from wood. Many times, wood will split, warp, twist, splinter and/or rot due to exposure to the environment, and particularly to moisture. These issues become even more problematic on upper decking surfaces where water can collect.
To address the issues with wood decking, several manufacturers now offer decking materials constructed from composite materials, which can include thermoplastic resins and in some cases cellulosic fillers. These decking materials typically are formed as elongated boards. The boards are constructed by extruding composite materials through a high pressure extruder. The resultant composite boards are more resistant to warping, splitting and splintering than conventional wood boards.
An issue with composite boards, however, is that while weight is reduced, these boards typically have a stiffness, when measured by the flexural modulus, that may be only 10%-50% of that of wood. Accordingly, composite boards used in a decking application, typically must be substantially larger than corresponding wood boards that they are designed to replace. Alternatively, the spans between underlying structures, such as joists must be significantly reduced to accommodate the less stiff composite boards. As a result, more materials and time must be used to produce a sturdy, supportive substructure when using conventional composite boards.
There remains room for improvement in the field of composite decking, particularly in relation to improving the stiffness and tension characteristics of composite boards.